Some dietary supplements are associated with an increased risk of death in older women, according to a study released Monday in the Archives of Internal Medicine. In an analysis of about 39,000 women tracked over 19 years, researchers led by a team at the University of Minnesota found that those who took multivitamins, vitamin B6, folic acid, magnesium, zinc, copper and especially iron died at higher rates during the course of the study than those who did not take supplements.